DESCRIPTION (Verbatim from the Applicant's Abstract): The goal of this research program is to develop an ultranarrowband imaging detector which can be used for in vivo biomedical imaging. The device will be capable of providing real time velocity information in images of arterial blood flow and compositional information via selective Raman imaging. Functioning in the near infrared, it will be capable of obtaining images at tissue depths of up to several cm. The extremely high spectral resolution is achieved by using an atomic vapor as the active sensing element. Laser pumped multi-step resonance ionization provides a near unity quantum efficiency and a large solid angle for optical collection, approaching 2m sr, is possible. When coupled with a microchannel plate amplification stage and a CCD detector, such devices offer unparalleled performance for specialized imaging applications. This research project will develop and optimize resonance ionization image devices using mercury and cesium as active elements. Studies will include the ionization spectroscopy of Hg and Cs, optimization of the detector response function (spectral bandwidth, quantum efficiency, spatial resolution), design and development of functional devices for imaging in biomedical systems and finally, applications to imaging of arterial blood flow in patients with peripheral vascular disease and the Raman imaging of arterial plaque.